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COMMERCE CITY, Colo. (KDVR) – A mass COVID-19 vaccination site at Dick’s Sporting Goods Park was closed Wednesday after 11 people experienced adverse reactions following Johnson & Johnson vaccine shots. That batch of the vaccine has been sequestered by the state as it’s being investigated.

Centura Health, which runs the site along with the state, said more than 1,700 people had received vaccines before shots were halted, putting the percentage of people who had adverse reactions on-site at about .62%.

Medical staff on site Wednesday determined two people needed to be taken to the hospital for additional observation “out of an abundance of caution,” Centura said. Those two people were treated and released the same day.

The reactions ranged from low blood pressure – which prompted hospital visits – to more mild symptoms like nausea and dizziness, according to Centura. The nine patients not taken to the hospital were treated with juice and water.

Overall, Centura said it will continue using all three COVID-19 vaccines, including Johnson & Johnson’s. At a Thursday news conference, Centura officials urged people to get vaccinated, and said it was not seeing cancellations at its sites.

People who were sent home from the Dick’s Sporting Goods Park site on Wednesday had their vaccination slots rescheduled for Sunday, when they will receive the Pfizer vaccine. Use of the Johnson & Johnson vaccine is planned at other sites Centura runs, including the Colorado State Fairgrounds in Pueblo on Saturday.

In a statement, the state health department said, “The state has no reason to believe that people who were vaccinated today at Dick’s Sporting Goods Park should be concerned. Adverse reactions are typically immediate.”

The state said the reactions at the one site are not impacting other vaccine providers, emphasizing that the “actions taken today were out of an abundance of caution.”

Johnson & Johnson released a statement Thursday. “We carefully review reports of adverse events in individuals receiving our medicines and vaccines,” the company said. “We are collecting the necessary information, including from the local vaccination center, to assess these reports.”

The vaccination site, which was scheduled to close at 5 p.m., shut down around 3:30 p.m. and sent home 640 people who had been waiting in line for hours for the vaccine.

“Our goal is to continue to vaccinate Coloradans as quickly as possible while keeping our patients’ safety at the forefront,” Centura said in a statement.

When getting any COVID-19 vaccine from any provider, patients are monitored for at least 15 minutes to see if they experience reactions. The monitoring time is longer for anyone who has previously had a reaction to a vaccine.

The state health department said there have been 10 previous reactions documented at Community Vaccine Sites prior to Wednesday, according to VAERS, the Vaccine Adverse Event Reporting System. The Centers for Disease Control and Prevention and Food and Drug Administration manage that reporting system.

Nationally, over 4.5 million people have received the Johnson & Johnson vaccine. The CDC had reports of 129 of those patients who had side effects severe enough to go to the emergency room or doctor’s office.